Vacuum-control apparatus



J. J.' GRAFFLIN VACUUM CONTROL APPARATUS Jan.. s, 1924.

Filed Aug. 13, 1921 2 Sheets-Sheet 2 Patented Jan.. 8, 1924.

UNITED VS'I'A'FESy PATENT ,ol-FiCE-.v

JOHN. J'. GRAFFLI'N, 0F ATLANTA, GEORGIA. v

VACUUM-CONTROL ArPAiiATi/Is.

Application led August 13, 1921. Serial No. 492,181.

T 0 all lwhom t may concern Be itv known that I, JOHN J. GRAFFLIN, a

citizen of the United States', and a resident' of Atlanta, county of Fulton, State of Georgia, have invented certain new and usefui Improvements in Vacuum-Control Apparatus, of which the following isa specification.

My invention relates broadlyV to systems in which, for one purpose or another, it is desired tonormally maintain a vacuum and there may be coupled with this kbroad purpose the additional feature ofthe mechanism automatically actuated or set in motion when the vacuum is definitely broken. An example of such a combined system is illustrated in a prior application filed by nie on April 25th, 1921, Serial No. 464,280. In sai-d prior application, I have set forth a dry pipe sprinkler system for fire protection and in that instance the 'vacuum is normally maintained to Akeep the interior of the sprinkler pipes dry .and upon definite breaking of the vacuum `as by the opening of ay sprinkler head, the mechanism automatically trips a hydraulic valve, which admits the water into the sprinkler pipes. The'mechanism shown in the present application is, in some particulars, an .improvement on the broad principle illustrated in said prior application and some of these features ai'e claimed broadly in the present case.

The vacuum control apparatus, according to the present invention, comprises, in the first place, any suitable form of vacuum pump for exhausting air from the system to be evacuated, a novel form ofy check valve through which'the exhausted air is removed from the system, apressure responsive de-y vice by which the vacuum pump is thrown into operation to restore the vacuum to normal when variations in the vacuum Ahave to the accompanying drawingto clearly set. forth the principles employed and to en invention.

In .said drawings Figure 1' represents a diagrammatic view" in elevation of apparatus constructediin acl" cordance with my invention.

Figures2 yand 3 are deta'i v. devices referred to.

tus sho'wn in Figure 2.

v y reieya'ions er@ `parts actuated by 'the pressure 'responsive i ,ceitainfoperating connections ofthe appara- Fifrure 5. is a Vhorizontal section onthe" line of Figure 1, andA Figure 6 is a plan view showing mounting of one of the pressure responsiveA devices, with a part in section.

. Referring in detail' to said drawing, 10v indicates a vacuum' pipe, which may ;lead'` y im@ 'a relatively large chamber i'i, from which a vacuum pipe.12'leadsjthrouglilan inclined enlargement '13 containing a body ofrmercury 14 and ,ad body of water 15V.v

From. the chamber 13, a vacuum pipe 1,6y leads into a vacuumppump 17, which maybe actuated by water supplied Vby pipe' 18 `under the control of a piston valve (19.'l Pis-A ton vvalve 19 delivers through the pump 17,'

which discharges the water and exhaustedVl air throughlp'ipe 20, which hasza" slight'yi'ip'- lward offset, as indicated at 21, and:finallyl discharges through the outlet 22 into 'a waste `pipe 23. Upon opening the piston valve y19,

water passes through the vacuum pump 117 y land thus withdraws air through` vacuum pipe 10, 'chamber 11, pipey 12, mercury'f14, water 15 and pipe 16. The Vbody' ofv niercury 14, together with thebody of' water' 15, providesa seal o r liquidclieckfvalvefor preventing the return of air througlithe pipes described. In'the operation of exhaustinglthe system, the mercury. isdrawn jinto the enlargement forming 4chamber 13, after' which the mercury returns into'the position indicated in Figure-.1 of the drawings. The passage of air bubbles through the mercury has, in practice7 .a tendency to carry sniall drops of mercury ,out ofthe systeniandf'to .prevent this, the body of water-'.15 i`s` .niaintained upon the surface df theme'rcuiy'. This layer of water' effectively washes the air of mercury. The'u'pward offset 21 ofthe pipe 2O performs the functionof retaining I a small quantityof water'infthe-,pipe 4'2O when the supply .is discontinued' and this vpin to hold them in place.

remnant of water automatically drains back into the check valve chamber 13 where it forms the body oi' water 15 described.

The means for automatically actuating the piston valve 19 will now be described. Leading from the chamber 11 or other evacuated part of the system is a vacuum pipe 24, from which a branch pipe 25 communicates with the top of a mercury reservoir 26. From the bottom of the reservoir 26, a pipe 27 leads downwardly into a mercury Well 28, which forms part of a suspended or tloating cup 29 open to the atmosphere. The

mercury cup 29 is provided with a trunnion ring 30, by which the cup is pivotally supported in the free ends of levers 31 (see Figures 1 and 6). The position of the mercury cup 29 within the trunnion ring 30 is adjustable as to height by loosening the screws 32. The levers 31 are pivoted at 33 upon a journal rod mounted in a U- shaped bracket 34, which is suitably secured on the wall of housing 35. A pair of triangular plates or arms 36 are similarly pivoted on journal rod 33 and are fixed to the levers 31 by cross pins 37. Spacing sleeves 38 and 39 are mounted on the journal 33 and cross pin 37 between the plates 36 to space apart the levers and arms and they may be keyed Vto the journal rod and cross The lever 31 with the plates 36 constitute a bell crank lever actuated by the mercury cup 29 and its contents, as will be described. n order that the movement of this bell crank lever may be transmitted to open and close the piston valve 19 of the vacuum pump, the

vfreevends or extremities of the plates 36 are connected with a link 40, which has a slot 41 in its upper end, through which slot passes a transverse pin or rod 42, mounted in the extremities of the plates 36. Sleeves 43, keyed on cross pin 42 maintain the upper end of the link 40 in proper position. The lower end` of the link 40 is deflected at 40a and straddles the piston valve 19. It is suitably connected as at 40b with the piston stem of the valve 19 so that reciprocation of the link opens and closes the valve. The mercury cup 29 is supplied with a body of mercury of suitable quantity and this body of mercury is partly drawn up into the stationary reservoir 26 when the normal vacuum is being maintained within the system. As vacuum decreases, more mercury flows into the well of mercury cup 29 and thus increases the weight or load sustained by the levers 31. This variable weight of mercury is normally counter-balanced by a counterbalance weight 44 mounted between levers 45, which are i'ulcrumed rto the free ends of links 46, journalled at 47 in a U-shaped .bracket 48 (see Figure 5). The other ends of the levers 45 are connected as shown in Figure 1 with the ends of pivot pin 42 o-n counter-weight 44.

Laveno@ plates 36. With this construction, the actuation of link 40 is dependent upon .the opposed relative forces of counter-weight 44 and mercury cup 29. The values of these forces are so proportioned that, during the existence of a vacuum in the system within prescribed normal limits, the force of counter-weight exceeds the gravity eii'ect of the mercury cup 29, by reason of the quantity oil mercury withdrawn from cup 29 into the reservoir 26. When the vacuum decreases, the mercury will flow from reservoir 26` into cup 29 to maintain the hydrostatic head of mercury corresponding to the diii'erence between internal and atmospheric pressures. An important feature of the improvement in the present invention resides in the provision of an enlargement of pipe 27 into the form of a reservoir 26'of relatively great transverse area so that the quantity of mercury which is transferred to raise or lower the surface within the reservoir is very great as compared with that corresponding to changes in surface level within the rest of the mercury tube. A similar consideration applies to the enlargement forming the cup 29 above the mercuryk well 28. By the use of horizontally extended reservoirs 26 and 29, the variation in weight ot mercury supported by cup 29 or withdrawn therefrom with a relatively small change in pressure within the evacuated system may be designed to give the desired amount of power for operating the vacuum pump valve 19. In other words, the control may be made very sensitive while gaining ample actuating power for the valve. The lost motion connection between levers 31 and link 40 permits a relatively free movement of the lever downward during the first part of its descent. It will be observed that, as the levers 31 descend, the cup 29 is lowered with respect to the reservoir 26 and, hence, introduces a further withdrawal of mercury from the reservoir 26. In this way, the condition of instability once started by the increase of pressure within the Vvacuum is built up, as it were, by the initial response to the pressure change. By the time the lost motion of the levers 31 with respect to link 40 has been taken up, the weight of mercury. which has been introduced into the cup 29 has become ample to supply the power required for actuating the valve 19 against the The apparatus above described represents what I may term the normal vacuum control and, in practice, is set to turn on the vacuum pump when the vacuum has dropped below the desired normal limit and to shut oit the vacuum pump when the normal vacuum has been restored.

The U-tube 50 may be embodied in the" apparatus, suitably connected with the pipe 24 and open to atmosphere at its other end so that the mercury column 51 may visually Larra-ecey indicate the vacuum which exists at the time within the system.

An additional feature ofl importance, which may be incorporated in certain systems, comprises a construction, which may be in general similar to the normal vacuum control mechanism but adapted to aetuate some'extraneous mechanism upon definite destruction of the vacuum. Such an extraneous mechanism may, for example, be a hydraulic valve for sprinkler systems, such as referred vto in my prior application above mentioned. To illustrate this portion of the apparatus, I'liave shown a hydraulic discharge pipe 60 normally closed by a valve bar 61, pivoted at 62 to the bracket 68, mounted on pipe 64. The valve bar 61 constitutes ahydraulic trip, which, it may be assumed, permits the extraneous mechanism to come into operation by opening the discharge pipe 69. The outer end of the trip bar 61 is pivoted at 65 with a link 66 provided at its upper end with a latch element such as hook 67. This hook 67, as clearly shown in Figures 1 and 3 of the drawings, may be hung from a roller or sleeve 68 mounted on cross pin 69 between plates 70 similar to the plates 36 above described.

The outer ends of the cross pin 69 may-beV engaged by the ends of counter-balance levers 71 carrying a weight 72 and pivoted against the free ends of links 7 3 fulcrumed at 74 in a bracket 75. The plates 70 are journalled at 76 in a U-shaped bracket 77 and have secured to them the levers 78, which engage the trunnion ring 79 of a mercury cup 80 into the well 81 of which the mercury pipe 82 from mercury reservoir 83 dips. A vacuum pipe 84 connects reservoir 83 with the evacuated system so that the inner surface of the mercury is exposed to vacuum and the outer surface to atmosphere, as already described in connection with the normal vacuum control. reservoir 83 in this instance is lower than the reservoir 26 and the cup 8O may have a normal position of stability on the same level with the cup 29. In other words, the difference in elevation between cup 8O and reservoir 88 is less than the difference in elevation between cup 29 and reservoir 26. Thus, with the counter-weight properly designed, this mechanism will remain out of operation so long as the vacuum is maintained within the normal desired range. Upon definite destruction of the vacuum, however, as by the opening of a sprinkler head or other thermostat-ic valve, the cup 80 will depress the levers 78 into the position shown in dotted lines in Figure 1 and during this operation, the link 66 is unlatched from the roller 68, this act-ion being positively insured by the provision of an abutment stop 85, which may have an antifriction roller 86 mounted` in the lateral The path of the upper end of link 66. When this link is released, the trip bar 61 falls by gravity andv water pressure from pipe 60, where-upon the 'water is discharged from the pipe and the extraneous mechanismis permitted to come into.` operation.

lt is desired to 'mention particularly that the invention herein shown and described is not to be understood as limited to use Vin a system such as setforth in my said prior application for patent. In said'prior application, the vacuum is maintained within the sprinkler pipesthemselves but the vacuum system in the present invention maybe separate from the sprinkler pipes or not. In fact, l contemplate, by the presentinvention, one embodiment in which the vacuum system, such as pipe 10 and chamber 11 are entirely distinct from the water pipes of 'a sprinkler system but may be employed as acontrol in buildings having'sprinkler systems provided with a main valve, which according to my invention, can, lfor example, be actuated by the discharge of water from pipe 60. It is equally obvious that thefprinciples of construction and operation herein shown and described may find widely divergent applications entirely apart' from the question of tire protection and it will bei understood, therefore, that invention is: not

tobe understood as limited to any particular use.

The chamberf'll, shown herein, maybe regarded as a cushioning device for minimizing the transmissioncf pulsations from the vacuum pump to the control devices and it may also serve as a reservoir of suiicient capacity to receive and retain water of condensation or leakage during intermediate idle periods when the vacuum pump 19 is not operating. Obviously, water collecting in the reservoir 11 will, upon the next operation of the vacuum pump, be withdrawn through the pipe 12.

I claim; l

1. Apparatus responsive to change of pressure comprising in combination a chamber, a liquid reservoir exposed to the pressure within said chamber, a second reservoir exposed to a different pressure from that .in the chamber, one of said reservoirs being movable with respect to the other, connecting means whereby said apparatus may be governed by the movement ofthe movable reservoir and a conduit of relatively small sectional area leading from lone of said reservoirs toV the other; said reservoirs adapted to contain alternately a quantity of liquid transferable thru said conduit from one to the other upon change of pressure within said chamber, to effect movement of the movable reservoir by gravity.

2. Apparatus responsive to change of vacuum comprising in combination a vacuum chamber, a liquid reservoir exposed to the vacuum within said chamber, a second reservoir exposed to atmospheric pressure, one of said reservoirs being movable with respect to the other, connecting means whereby said apparatus may be governed by the movement of the movable reservoir and a conduit of relatively small sectional area leading from oneof said reservoirs to the other; said reservoirs adapted to contain alternately a quantity of liquid transferable thru said conduit from one to the other upon change of pressure within said chamber, to eect movement of the movable reservoir by gravity.

3. Apparatus responsive to change of vacuum comprising in combination a vacuum chamber, an upper liquid reservoir exposed to the vacuum within said chamber, a lower reservoir exposed to atmosphere, one of said reservoirs being movable with respect to the other, connecting means whereby said apparatus maybe governed by the movement of the movable reservoir and a conduit of relatively small sectional area leading from one of said reservoirs to the other; said reservoirs adapted to contain alternately a quantity of liquid transferable thru said conduit from one to the other upon change of vacuum within said chamber, to effect movement of the movable reservoir by gravity.

4. Vacuum governed apparatus comprising in combination a vacuum chamber, a vacuum pump, an upper stationary liquid reservoir in communication with the vacuum ramene chamber, a lower movable reservoir held in its elevated position by a counter force to stop the pump, connecting means whereby said pump may be governed by the movement of the movablel reservoir and a restricted rorricellian connection between the reservoirs, whereby a slight drop in level of the liquid in the upper reservoir -will transfer the bulk of the liquid to the lower reservoir and overcome the balancing` force so as to start the pump. i

5. Apparatus responsive to change of pressure comprising in combination a chamber, a liquid reservoir exposed to the pressure within said chamber, a second reservoir exposed to a dierent pressure from that in the chamber, one of said reservoirs being movable with respect to the other, connecting means whereby said apparatus may be governed by the movement ofthe movable reservoir and a conduit of relatively small sectional area leading from one of said reservoirs to the other; said reservoirs adapted to contain alternately a quantity of liquid transferable thru said conduit from one to the other upon change of pressure within said chamber, to edect movement of the movable reservoir by gravity, the said connecting means being yprovided with lost motion to allow part of the liquid to transfer from one reservoir to the other before meeting the resistance of the apparatus to be moved.

JOHN J. GRAFFLlN. 

